<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        * {
            margin: 0;
            padding: 0;
        }

        ul {
            display: flex;
            border-bottom: 2px solid #e01222;
            padding: 0 10px;
        }

        li {
            width: 100px;
            height: 50px;
            line-height: 50px;
            list-style: none;
            text-align: center;
        }

        li a {
            display: block;
            text-decoration: none;
            font-weight: bold;
            color: #333333;
        }

        li a.active {
            background-color: #e01222;
            color: #fff;
        }

    </style>
</head>
<body>

<div id="app">
    <ul>
        <li :key="item.id"  v-for="(item,index) in list">
            <a href="#" @click="targetItem=item.id"  :class="{active:item.id===targetItem}">{{ item.name }}</a>
        </li>
    </ul>
</div>
<script src="https://cdn.jsdelivr.net/npm/vue@2/dist/vue.js"></script>
<script>
    const app = new Vue({
        el: '#app',
        data: {
            targetItem: 1,
            list: [
                {id: 1, name: '京东秒杀'},
                {id: 2, name: '每日特价'},
                {id: 3, name: '品类秒杀'}
            ]

        }
    })
</script>
</body>
</html>